The present invention relates to an installation for feeding sheet metal blanks to a first working stage of a multi-stage press, with feeding means for the removal of sheet metal blanks from a supply stack and for the deposit in an intermediate deposit station, with transfer rails adapted to be driven in the transfer direction, in the lifting and lowering direction and in the closing and opening direction and with gripper tools attached thereat for gripping the blanks in the intermediate deposit station and for the transport of the blanks to the working stages.
Initially, individual sheet metal blanks are fed to the tools, respectively, tool sets in presses such as gang presses, multi-stage presses and large-part gang presses, which blanks are seized by active gripping devices, clamping gripping devices, for the transfer from an intermediate deposit station into the first working stage which, for the most part, is a deformation station. The active gripping devices are secured at transfer rails and are movable together with the same in the closing and opening direction, in the lifting and lowering direction and in the transfer direction. The movement in the closing and opening direction serves for the guidance of the active gripping devices to the blanks, respectively, correspondingly formed passive gripping devices to the workpieces, for the release, respectively, the deposit of the workpieces in the following working stage and for the guidance of the gripping devices out of the tools. Heretofore, it was necessary to seize larger sheet metal blanks deposited in the intermediate deposit station by active gripping devices during the standstill of the transfer rails after movement thereof in the closing direction. The time for gripping and for closing the active gripping devices reduces the output of the press.
A feed installation for sheet metal blanks to a first working stage of a stage press is described in the U.S. Pat. No. 4,259,052 which has the features described hereinabove. The blanks are removed from a supply stack by means of suction lifters of a vertical lifter, are taken over in the lifted-up position by suction cups of a horizontal conveyor and are deposited on deposit means of an intermediate deposit station. The feed takes place at the rhythm of the press and in synchronous movement with respect to the transfer rails. The blanks have to be seized during the standstill of the transfer rails so that waiting periods result which reduce the output of the press.
The object of the present invention resides in the provision of an installation of the aforementioned type, by means of which the blanks are seized during the lift movement of the transfer rails by active gripping devices attached thereat. For that purpose, the blanks are to be lifted during the vertical movement of the active gripping devices by means in the intermediate deposit station.
The underlying problems are solved according to the present invention in that the deposit means of the intermediate deposit station are supported liftable and lowerable in guide means, and in that movement-transmitting means are arranged between the deposit means and the transfer rail drive (enclosed drive mechanism)--with a direct pick-up of the movement in the lifting and lowering direction from the transfer rail drive, the movement transmitting means are then arranged between the deposit means and at least one transfer rail--for a movement of the deposit means synchronous in at least the lifting direction of the transfer rails.
In addition to a shortening of the cyclic operation of the transfer rails which leads to a higher output of the press, it is furthermore of advantage that the blanks are aligned already with the removal movement by the horizontal conveyor for the predetermined passage through the press.
These and other objects, features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, two embodiments in accordance with the present invention, and wherein: